Electron beam controlling system



Nov 2911949 H. w. G. SALINGER ELECTRON BEAM CONTROLLING SYSTEM 3 Sheets-Sheet l Filed Oct. 7, 1946 INVENTOR HANS W.G.SAL|NGER ATTORNEY NGI Nov. 29, 1949 H. W. G. SALINGER ELECTRON BEAM CONTROLLING SYSTEM' 5 Sheets-Sheet 2 Filed Oct. '7, 1946 INVENTOR HANS W. G. SALINGER ATTORNEY N0V- 29, 1949 H. w. G. sALlNGER 2,489,328

ELECTRON BEAM CONTROLLING SYSTEM Filed Oct. 7, 1946 3 Sheets-Sheet 5 F I G. 4

voLTAGEVsuRcE VOLTAGE souRcE F I G. 5

VOLTAG E SOURCE VOLTAGE souRcE V2 INVENTOR HANS W.G. SALINGER ATTORNEY Patented Nov. 29, 1949 ELECTR'oNiBEMooNTRoLIJmG.SYSTEM Corporation, acorpoxation of'ndian'a Y Applidatiroxctobei', V1946, Serial No. 701,722

Claims:A (Cl. 31E-424V# This invention' relates'i-.to ssysterns: if or i control- .1

ling a `beamV lof electren'sfand particularly, has: .f referencei Vto yvoltage distribution .networks-Ilfor` impressing l the' :deflecting and centering 1 voltages f upon I the field producingge'lectrodes'of acathcdew raytube.

According Ito conventional practicefpthe irelec i tron rbeams Lof cathodexray;,tubesfihavelbe'enfdew4 flected over theirvassociated target electrodes `ei`y therfby electromagnetic or by electrostatic de'- ecting l`systems.`

'l0 In-v @the cases of tubes f .wherein-1Y electrostatic deecting :systems have been used, a plurality.` of pairs 'of yfield producing electrodes i have-been employed for producing the necessary r defiecting eldsf It iis usual `to provide twofsuch pairs of electrodes,

mounted-at 90 degreesrelative toone1another;

In suchapparatus 'the electrodes or each pairfareplacedfopposite to one@ another and the twoI pairs `of Velectrodes-aretions by the impression-upon vtheetwdpairs,of

electrodes` of Vsuitable scanning` voltages;

Sucha deflecting` system is particularly.we11 adapted for .use in cathoderay tubes .wherein anelectron beam of relatively Vsmall.cross-sectional area `is used. Typical examplesof such tubesare found in Oscilloscopes, television. .image reproducing tubes, and thelike. i

In certain' tubesfsuchas va television image dissector, the 'electron beam which is to be de` lectedis'of considerably` larger crossfsectnal area. Heretofore," it has' been generally'customary todeflect such an'electron'beam bymeansof electromagnetica'lly produced deflecting elds for" the reason that electrostatic"deectirfofthese' electro-n bearnsl'has not-been particularly' easy to' the'two` pairs of electrodes are' mountedin` two different planes spaced fromone anotheralongm theipath of the electron beam: 'Such a displaceiment of the delecting electrodesihas been nec*- essar-y'in orderto avoid'a'distorton'i'of the'elecftrostatic field which generallyresults by 'mounti" same plane. As a result `of-such a distortec'l'f'iield,V

the beam deflection ceasesto be a linearfunc` tion'forthe deflection voltage impressed upon the electrodes;

There previously has been-proposed-a deflecting i isystem' particularly 'adapted Lffor' use' "inl ari v image2=dissector `where'byeto producersd composite electrostatic eld in" on plane which'is capable ijectfmatter-of PatentNo. v22971949 granted'to P.'

T. Farnsworth onOctober 6, 1942, for a Deflecting system. This patentL comprisesa cathode ray tube such as-an-imagedissector which is provided with-1a pluralitytofv-pairs of deflecting elements fall mountedin` the` sa`me^plane 4and surrounding a portioneof the pathof the electron beam. In one form of-thelpatented structure, a number of elongatedl rodslvare-kused" as--the deflecting elements.V -Each of these rods'vextends generally longitudinally of the-`electronbeam path. The high frequency-and -low' frequency deileeting'voltages are-impressed upon-theseelectrodes by means of a voltage distribution network. Each one -of the deiectingV .electrodes has `.im-pressed -thereon a lpredetermined proportion of TeachL of the deectingsvoltages. depending upon` its particular locationrelative to `the two coordinate scanning direetions. Bythis. meansyit has been determined that the desired electrostaticdefiecting field may be `Vproduced without:r appreciable i distortion whereby `to effectthexdeection ofan electron beam, particularly onehaving a crossesectional area .of considerablemagnitudm over a target electrode in two coordinate-directions.

In accordance with the subject matter of the Farnsworth rpatent,-the voltage distribution system comprisesa network of impedances arranged in such` a -mannerthat-the two deecting voltages are separated or decoupled in accordance with the respective frequencies thereof. Inasrnuch as the vvertical defiecting voltage hasa frequency of the order oi cycles per second and the horizontal de'flectig voltage. has a frequency of the order of 15,600 cycles .per second,- according to present `television standardsrthe frequency separation or decoupling of the two defiecting voltages is accomplishedquite readilyat the fundamental frequencies.'

However, since both of these defiecting volt-- ages have complex'wave forms, generally that of a saw-tooth, 'theiealso is present, Ain addition to the" fundamentalfrequenciea number 'of harmonic frequencies. In order'tomaitain'the desired linearity; vit is essential vthat fa conside'i` v :nth harmonic. As a consequence it is necesy to maintain the separation or decoupling the two deflecting voltages through an appre- ,ble band of frequencies. In the case of the ftical deflecting voltage, the frequency band tends from about 60 to about 900 cycles per zond. In the case of the horizontal deecting ltage, the frequency band extends from about ,000 to about 200,000 cycles per second. Thus,

reason of the frequency band widths required be maintained, a deiiecting voltage distribun syst-em operated on the principle of freency discrimination has not been entirely sucssful, especially when operation is attempted the relatively high horizontal deecting freencies required for 525 line scansion, accordg to present television standards.

It is well known that, when deilecting an elec- Jn beam over a target electrode, the beam first .1st be oriented relative to the target. In prace, this is known as centering the electron beam.

the case of an image dissector, particularly, it

nerally is preferable to direct the electron beam that, in the absence of any deiiecting elds, the nter of the beam falls in line with the scanning lerture. Then, when the beam is deflected over e aperture, the deflecting movement thereof ll be symmetrical in all directions with a conquent minimizing of distortion effects. Inasuch as the centering of an electron beam, once ected, is not ordinarily subject to change, a ald of substantially constant intensity is emoyed for this purpose Customarily, this ileld produced by the impression of a direct current ltage upon the field producing deiiecting elecodes. Then for deilecting purposes, a saw-tooth iltage is superimposed upon the direct current ltage to achieve the desired results. Where an ectrostatic dissector, such as that disclosed in .e Farnsworth patent referred to, is used, the distant unidirectional voltages for centering the ectron beam must be impressed upon the various :fleeting elements in suitable respective propor- )ns to create a constant uniform field.

It is an object of the present invention, there- Ire, to provide a novel distribution system for multaneously impressing both high frequency 1d low frequency deflecting voltages upon a plu- |.lity of electrostatic electron beam deflecting ectrodes whereby to secure a beam deflection hich is a linear function of the deflection volt- ;es and at the same time whereby the two deecting voltages are effectively decoupled at subantially all frequencies thereof.

Another object of the invention is to provide a istribution network for impressing both high nd low frequency scanning voltages upon a lurality of electrostatic electron beam deflectlg elements which operates entirely independitly of frequency differences of the two deflectig voltages.

A further object of the invention is to provide distribution network for impressing upon a lurality of electrostatic electron beam deecting lements substantially constant unidirectional oltages for orienting an electron beam relative i a target electrode.

Still another object of the invention is to proide a novel distribution network for impressing pon a plurality of electrostatic electron beam electing elements electron beam centering voltges in suitable proportions to produce a sub- ;antially constant beam deflecting eld, together rith facilities for .varying in the proper propor- 4 tions the individual voltages impressed upon the respective deflecting elements whereby to alter the orientation of the electron beam relative to the target electrode.

A still further object of the invention is to provide a system including a distribution network for impressing upon a plurality of electrostatic electron beam deflecting elements, both high frequency and low frequency voltages for deecting an electron beam over a target electrode, together with unidirectional voltages for orienting the beam relative to the target electrode.

In accordance with this invention there is provided a tube which has facilities for developing an electron beam and directing it toward a target electrode. The tube is also provided with a plurality of eld producing electrodes which are uniformly spaced in a circle around the path of the beam. In general, 4k: electrodes are required, k being equal to any Whole number. These electrodes, when energized by suitable voltages in accordance with the invention, are employed to move an electron beam relative to the target electrode. In order to effect the beam movement according to a predetermined scanning pattern deflecting voltages are impressed upon the electrodes in respective proportions to produce in the path of the beam a homogeneous eld which varies periodically in magnitude as arfunction of time. In order to suitably orient the electron beam relative to the target electrode, unidirectional voltages are impressed upon the electrodes to produce a homogeneous field of relative constant magnitude. These voltages are impressed upon the electrodes by suitable connections to one or more voltage distributing networks.

Such a network consists of a balanced bridge arrangement of a plurality of impedance devices. The impedance devices are connected so as to provide the network with a mirror electrical symmetry about four aXes of the network, each being located at angles of 45 degrees relative to one another. The connections of the impedance devices is such that the network is provided with two pairs of conjugate corner points. Voltages VI and V2 are connected to the respective pairs of corner points. The network further is provided with intermediate tap points on the various branches thereof. As many tap points are provided as there are eld producing electrodes in the tube and the tap points are connected respectively to these electrodes. In order to produce a homogeneous field in the path of the electron beam the impedance devices of the network are proportioned so as to impress upon any given one of the electrodes located at an angle A relative to an axis of symmetry of the electrodes, a voltage proportional to V1 sin A-l-V2 cos A.

In one form of the invention one such network is employed to impress the highfrequency and the low frequency deflecting voltages upon the tube electrodes. Another network of a similar character is provided to impress the orienting or centering voltages upon the electrodes. In conjunction with Athe centering network there are provided facilities for varying the magnitudes of the energizing voltages impressed upon the corner points of the network.

In another form of the invention there is provided a single network of this character for distributing both the deflecting and the centering voltages to the tube electrodes.

For a better understanding of the invention, together with other and further objects thereof,I

reference is vmade to the iffollowingalescription, taken in connection withx'the uaccompanying drawings and its scope .will be pointedput in the appended claims.

In theaccompanying drawings:

Fig. 1 is a longitudinal.::sectional view`of a television image dissector tube having a' plurality of electrodes whereby.toeffect-.electrostatic rdefiection of an electronbeampver artarget electrode;

Fig. 2 is `a, schematic circuitdiagram of apparatus embodying the invention lwhereby suitable deiiecting and centering :voltages are impressed upon the tube deecting-electrodes;

Fig. 3 is a schematic circuit diagram ofi apparatus embodying another form 'off the invention wherein one voltage Vdistributing'networkis fused:

for both thedeflectingiandfthe centering -volt ages;

Fig. 4 is another'A schematic dlagramlof apparatus embodyingthe inventionL-in still Nanother form wherein one netwerkI is -usedfor both deflecting and centering voltages; rand Fig. 5 is a schematic circuit diagram of apparatus embodying.theinvention-wherein-a more complicated form of -network is used for `impressing `both the deflectingY anduthe centering voltages upon a tube having a relatively greater number of field producing electrodes.

Having reference now tofFig. 1- of the drawing, there is shown avtelevisionk image dissector tube ll. One end wall of the tube is provided with an optically plane-window I 2fand there is mounted adjacent the other end wallof the tube, a photoelectric cathode I3. The photosensitive surface of the cathode faces the window I2 so that an optical image may be projected through the window onto the cathode. The tube also is provided with a target electrode'lll located at one end of the tube adjacent the window`l2. The target electrodeisxprovided with a relatively small aperture I5 substantially of the size of an elemental area of the picture which it-is. desired to analyze. Preferably the aperture I5 is located on the central axis of the tube. In any case, it faces the cathode I3 Vso that electrons from the cathode may enter the target electrode .through the scanning aperture I5. .In accordance with generally preferred practice, ythetarget electrode serves as a housing f-or a multi-stage static electronmultiplier whereby a preliminary video amplification may be effected. The target electrode is maintained at a suitable positiveipotential relative to the cathode by meanssuch Aas a battery I6.

The tube Il also is provided withia plurality, twelve in the case illustrated herein, of elongated oleecting electrodes such as Il. 4 These electrodes may be in the form of relatively stiff wires or small rods and are spaced uniformly about the longitudinal axis of the tube-.adjacent the inner periphery of the tube envelope. Preferably, they extend from the region of thecathode I3 to a plane adjacent to the scanning aperture I5 of the target electrode. ,Eachfofthe deecting electrodes is connected through the tube envelope by means such as a conductor I8. `Inthis manner electrical c-onnections maybe made to each of the deiiecting electrodes. An electrically conducting wall coating I 9.also isfprovided onthe inside wall of thetube envelope. .This wall coating may be connected, as'shown,to-thetarget electrode Ill. The tube `addtionallyis provided with a focusing devicesuch as an electromagnetic coil l 20 mounted aroundV the iexteriorrportionf of thel `tube envelope V inlsuch La mannerthat it` substantiallycompletely envelopes the space between the cathode I3 andthe target-electrode I4. The focusing ucoil maybe energized from a suitable source of unidirectional voltage such as a battery 2l `which may be connected to the coil through an adjustableresistor .22. By this means the magnitude of the current flowing in the focusing coil may be adjusted suitably to produce the desired focusing of the electron beam within the tube.

The electrical connections to the voltage distributing networks according to one form of the present invention are indicated in Fig. 2 to which reference now will be'made. In this gure there is shown a `transverse section of the image dissector tube II. The deflecting electrodes are twelve in number and are identified by Roman numerals from I to XII in the well known manner of a clock dial. The connection of only the electrode I is shown complete to the voltage distributing networks, all other connections are similar and have merely been indicated so as not to unnecessarily complicate the drawing.

The deflecting electrodes such as I1 are coupled to a deiiecting voltage distributing network 23. In general this network resembles that of a Wheatstone bridge. It comprises a balanced bridge arrangement of a plurality of impedance devices. The arrangement of these impedance devices in the network and the respective values thereof is such that the network has a mirror electrical symmetry about four axes located at angles of 45 degrees relative to one another. The network consists cf four exterior branches 24, 25,26 and 2 connected in series as shown to form a continuous loop. Each of these branches such as the branch 213 is composed of three resistors such as 28, 29, and `3| connected in series and having a combined impedance equal to that of the impedance of each of the other exterior branches, and corresponding resistors in the respective branches are of identical impedance values. In addition, the network includes four interior branches 32, 33, 34 and- 35. Each of the interior branches is composed of two resistors such as 35 and 3l connected in series and having a combined impedance equal to that of the impedance of each of the other interior branches and corresponding resistors in the respective branches are of identical impedance values. The branches 32 and 34 are connected in series with one another and the terminals of this series arrangement are connected to one pair of conjugate corner points 38 and 39 of the network. Similarly the interior branches 33 and 35 are connected in series and to the other pair of conjugate corner points 4l and 42 of the network. The junction point 43 between the interior branches 32-34 and 33--35 constitutes the central point 43 of the network. In a preferred form of the invention the central point i3 is grounded for alternating currents through a condenser M.

A source 45 of high-frequency deflecting voltage which has a saw-tooth wave form is connected to the conjugate network points 33 and 39. Likewise a low frequency source 46 of deecting voltage is connected to the conjugate network points 4I and 42. Both of these deflecting voltages are supplied to the network in a push-pull relationship and are balanced relative to ground. The junction points between certain of the "resistors comprising the-network 23 are coupled respectively to the deecting electrodes such as I 'I ofthe image dissectortube II. .-Gnesucnvconnection is yshown completely from the junction point of resistors 28 and 29. This intermediate junction or tap point is coupled by a condenser 41 to the deflecting electrode I. Similar connections are made from the other junction points of the network resistors to the tube deflecting electrodes as indicated by the Roman numerals.

The impedance relationship between each of the exterior branches of the network 23 and each of the interior branches is somewhat arbitrary depending upon the effective network impedance desired. For simplicity of disclosure, assume that the combined impedance of each of the interior branches such as 33 is wi and that the combined impedance of each of the exterior branches such as 24 is we. In its simplest form, the network 23 is of such a character that the ratio zul/wz is equal to unity. In any case the resistors 28 and 3l and all others corresponding thereto each hasY a value which is equal to 0.367202. 'Ihe resistor 29 and all others like it has a value which is approximately equal to 0.266102. In each of the interior branches of the network, the value of each of the resistors such as 38 is approximately equal to 0.734w1 and the value of each of the resistors such as 31 is approximately equal to 0.266wi. In the interest of making the disclosure of a particular embodiment of the invention as complete as possible, one successfully operated device according to the invention employed resistors such as 28 and 3l having values of 5500 ohms, resistors such as 29 and 31 having values of 4000 ohms, and resistors such as 36 having values of 11,000 ohms.

For the purpose of centering or otherwise orienting the electron beam, the deectlng electrodes of the tube ll are coupled to a centering voltage distributing network 48. In form this network may be substantially similar to the network 23. In such a case it comprises four exterior branches 49, l, 52 and 53. It also includes four interior branches 54, 55, 58 and 51. Each of the exterior branches such as the branch 49 includes a series connection of resistors such as 58, 59 and 6I. Each of the interior branches such as the branch 55 includes a series connection of two resistors such as 53 and 54. As in the case of the network 23, the impedance values of all of the exterior ybranches and all of the interior branches are respectively equal. Also the ratio of the impedance value of each of the interior branches such as the branch 55 to that of each of the exterior branches such as the branch 49 is arbitrary but for convenience is taken as unity. In one practical embodiment of the invention the resistors 58 and 5I were of 180,000 ohms value. The resistors 59 and 64 had values of 133,000 ohms and the resistor 83 had value of 360,000 ohms.

One pair of conjugate corner points 65 and 56 of the centering network 48 is connected through respective resistors 8l and 88 to the movable contacts 69 and 1l, respectively of two potentiometers 'i2 and 13. The potentiometers are connected in series as shown with both terminals thereof connected to the negative terminal of a source of unidirectional voltage such as a battery 14. The junction point between the potentiometers 12 and 13 are connected to the positive terminal of the battery 14. For ease of manipulation and adjustment of the voltage impressed upon the conjugate points 85 and 68, the movable contacts 69 and 1l of the potentiometers may be mechanically connected as indicated by the broken line for simultaneous movement thereof by a single control knob 15.

The other pair of conjugate corner points 16 and 11 of the network 48 are similarly connected through resistors 18 and 19, respectively to potentiometers 8l and 82. Also in this case, a single control knob 83 is provided to adjust the two potentiometers 8| and 82 simultaneously. These potentiometers are connected in a manner similar to the previously described potentiometers 12 and 13 and are further connected to a source of unidirectional voltage such as 84. If desired, the batteries 14 and 84 may be a single source of voltage. With resistance values of the network taken as indicated hereinbefore, satisfactory operation of the apparatus has been obtained with these batteries having values of approximately 600 volts.

The junction or tap points between certain of the resistors forming the network 48 are conductively coupled to the deflecting electrodes such as Il of the tube ll. For example, the junction point between resistors 58 and 59 is directly connected to the tube electrode I. Other points of the network are similarly connected to the other tube electrodes as indicated. The central point 85 of the network 48 preferably is connected to the Wall coating I9 of the tube as shown.

In order better to consider the problem of producing a homogeneous deflecting eld, by means of a plurality of electrodes such as l1, assume that the total number of such electrodes is represented by n and that any particular one of these electrodes is represented by m. If then V represents the peak voltage impressed on the electrode XII, it is required to supply to electrode m a high frequency saw-tooth deflecting voltage of amplitude V sin and at the same time a low frequency saw-tooth delecting voltage of amplitude This general relationship may be applied to the particular embodiment of the invention disclosed herein. Consider for example the high frequency deflecting voltage required for electrode I. In this case m is equal to 1 and n is equal to 12. The high frequency deecting voltage which is required to be impressed upon the electrode I is equal to 0.866 of the high frequency voltage impressed upon the electrode XII. It may be seen that a voltage of the same amplitude and polarity must be impressed upon the electrode XI. Also the voltage impressed upon the electrode XII is equal and opposite in polarity to the voltage impressed upon electrode VI. Similarly electrodes V and VII have impressed thereon voltages whi-ch are equal in magnitude and opposite in polarity to the voltages impressed upon electrodes I and XI. In like manner the voltages which are required to be impressed on electrodes II and X and also upon electrodes IV and VIII may be determined from the general expression and are equal to 0.5 of the voltage impressed upon electrode XII. Obviously with respect to the high frequency delecting field, the voltage impressed upon electrodes III and IX is zero. This also is in conformity with the general expression.

In like manner it may be determined that, with respect to the low frequency scanning field, the voltage which is impressed upon the electrodes II and IV should be 0.866 of the voltage which is impressed upon the electrode III which latter voltage is equal and opposite in polarity to the voltage impressed upon electrode IX. A voltage ausgehe 9 whichistequal 1in magnitude but opposite in pola'ritysh'ould be impressed' upon' electrodes VIII and'X Asvoltage of the same polarity but of a magnitude* equal lto 0.5 of the voltage impressed upomelectrode III is required for impression upon eiectilods I and: V. A voltage of the same magnitude Buti of opposite' polarity should be impressed upon electrodes VII and XI. In this case the low 'frequency d'electing voltage impressed upbrrelectrodes VI andXlI Vis zero.

The` values" of the resistors comprising the network 23 Shave been chosen in their relationship to one another 'in such a manner that the voltage 'distribution required, as outlined in the preceding" paragraphs, may be secured." Anotl''er'consideration in the determination of the values of the network resistors is that it is necessary'ftominimize the eiect of the capacity of tle#'-deflecting electrodes. In a particular practical embodiment of the present invention it was determined 'that the capacity of one of the conductors is approximately 4.5 inicromicrofarads. Siichafcapacity",` ata frequency equal to the iiifteenthharmonic of the high frequency 'deectingfvoltageis4 equivalent 'to a reactance of 150,000 ohmssf Hence, it was necessary to so construct tlie networki23` that it would have a relatively lowresistancel Accordingly, each of the exterior branches such `as 24 and each of the interior branches *such as 32was made to have an impedance' of wapproximately 15,000 ohms.

Similar considerations should Ibe given to the construct-ion' of the centering network 48. Hava" centering network such as that specified previously, the potentiometers 12 and 13 may be f.

adjusted to move the electron beam in one coordinatedirection. The manner in which this isveff'ected by the network 48 in conjunction with thewpotentiometers 12 and 13 may Ibe more clearlyY understood if itis assumed that initiallythe adjustable contacts 69 and v'H of these potentiometrsareeach engaged with the center points on the-respective potentiometers. Inasmuch as each ofthenpotentiometers is connected in parallel across `the-batteryl, it is seen that the network points 65iand665ar'e at the same potential and, therefore; there is `no vertical centering voltage impressedfupon the electrodes such as l1; If now the control knob is manipulated to move .both of thefmovable contacts`69 andll in an upward direction as `viewedvr in the drawing, the contact 69fis moved toward a negative point on the potentiometer 12,- andffat the same time the `contactf I iis moved to a `positive point on its associat'd'potentiometer 13. The result of such an adjustment is to make the voltage impressed upon the point''negative, and 'at the same time to make tlieivoltageimpressed upon the point 66 positive-by ia like amount. The polarity and` magntude'iofithe voltages which are impressed upon'fth'etube electrodes by means of the connecti'ons thereof to the network 48 are eiective t-"fshift-the-'electric centering-eld to one side orltheother of the central axis of the tube depending up'on the sense of the adjustment of the knobiSl' Inthis case the electron beam will be moved horizontally.

A similar 'shifting of the electric field inthe' tube'inthe other coordinate direction is effected by suitable manipulation of the control knob 83 wherebythe-beam may be moved vertically.

It should :be noted that in the case -of both of thenetworks* 23 'fand 48,-the voltages Iby which it isilde'siredito move 'the `electron beam horizontally are-fii'npr-essedffup'onA the electrodes in a verticaly sense; Also; the vertical deiiecting voltages are impressed upon the electrode in a horizontal sense. The reason for this is the well-known fact that in a tube of the character described, a 90 degree rotation of the beam is effected between the cathode and the target electrode.

It should be evident from a consideration of the foregoing description of a specic embodiment of the' invention-that the principles underlying the invention are not4 necessarily limited to use with the tube having-just twelve deflecting electrodes. It iscontemplatedto obviously fall within the purview of the invention to have more or fewer defiecting electrodes. Also it -is to be understood that-theform ofthe network is not necessarily restricted to that shown in Fig. 2 so long as the Ibalancedwbridge requirement is fulfilled. It is consideredV that it is by reason of the balanced nature ofthe bridge that the necessary decoupling of the twodeiiecting voltages is secured. Likewise it should be obvious to one skilled in the art thatother types of impedances could be used to form .the deiiecting network. For example, in certain applications it may be considered-that the power consumption by a network such as that illustratively disclosed herein is too great. In such a case the network resistors may `be replaced with con'densers which would consume substan- .tially no power and .vet would give the proper deiiecting voltage distribution for both the high frequency and the low frequency deflecting fields. However, the capacitive reactances would have to be much smaller than any parallel resistances that might be present such as in the case where aV centering network such as 48 is employed in conjunction with this form of scanning voltage distributing network. Leakage current would also"be'afactor in` the design 0f such a network.

Ilbrderfor a device of the character described 40 to operate satisfactorily it is necessary as previcusly noted to maintain at a minimum the values Iof'any impedance elements connected to the"tube`electrodes.` Consequently, the effective resistance of'the deflecting network 23 is made relatively small. In one preferred form of ap- .paratu's'enibodying the invention, it is desirable t 'derive'theunidirectional voltage supplies for the-centering network 4B from the voltage divider network'lwhicli furnishes accelerating voltages to etheelectron'multiplier housed in the target anode |4'of 1. Ordinarily such a voltage supply is incapableof "furnishing current in any substantiall magnitude;A Therefore, in order to minimize the current drain'on' such a power supply, it is necessary'to 'so constructthe centering network l8r-that itseffectiv impedance is relatively high. Such'a network may then be connected effectively in parallel with .therelatively low impedance deiiecting network 23. Such an arrangement fur- 601 ther-idecreas'es the effective impedance connected totheftube electrodes so as to insure satisfactory operation of the tube and at the same time does n'otfrequire voltage supplies such as those reprel sented 'by`th`e batteries 'I4 and 84 which have to D furnishany appreciable current.

Nevertheless. an arrangement such as that illustrated in Fig. 2 requires a large number of circ'uit components to provide two voltage distributior'i networks, one for deiiecting and one lfoiv`cente'ring the electron beam. Furthermore ari'arrangemen't of this type requires decoupling ofthe'tw'networksfor direct current. A plurality `of condensers such as 41 are recuired for thispurpose. These'condensers must be of appreciablei'sizesoithat they may be employed in rom linearity by reason of the fact that coupling g :ondensers such as 41 are employed.

As will be disclosed presently, certain ones of iome other forms of the invention may be emiloyed to overcome the disadvantage of using cou- )ling condensers between the voltage distributng network and the tube electrodes. The adfantage of obviating the use of the coupling coniensers, however, is offset somewhat by the reiuirement that other sources of unidirectional foltages must be furnished which are capable 3f producing a greater flow of current than the eower system used primarily to furnish accelerat- .ng voltages to an electron multiplier.

Reference now will be made to Fig. 3 which iiagrammatically illustrates another form of the Invention. In this case the invention is shown in coniunction with a tube which is provided with eight ield producing electrodes. The tube is shown in transverse section. It is provided with eight elongated electrodes such as 92 uniformly spa ced in a circle around the interior periphery of the tube envelope. In this case the electrodes are situated in such a manner that the vertical and horizontal axes of the tube lie mid-way between two adjacent electrodes. The electron beam controlling elds which are to be produced by these electrodes are for effecting movement of the beam in the two coordinate directions corresponding to these axes.

The voltage distributing network which is used in coniunction with a tube havin?.l electrodes arranged in this manner is, as in all forms of the present invention. a balanced bridge arrangement of a plurality of impedance devices. The arrangement of the impedance devices is such that the network has a mirror electrical symmetry about four axes each located at angles of 45 degrees relative to one another. In this case, there is provided a network 93 which comprises four branches 94, 05. 06 and 91. These branches are arranged in a series connection forming a closed loop and corresponds in this respect to the exterior branches of the networks 23 and 40 of Fig. 2. Each of the branches is substantially identical to the others in total impedance and each branch comprises the series connection of three resistors. For example. the branch 94 includes resistors 98, 99 and |0|. The terminals of each of the branches are connected to terminals of two of the other branches as shown. The intermediate junction or tap points between the three resistors of each branch are connected respectively to two of the tube electrodes. For example, the tap point |02 and the tap point |03 of branch 94 are connected respectively to the tube electrodes I and II.

The corner points of the network are connected in coniugate pairs to the voltage supplies for producing the desired fields within the tube. For eiecting horizontal deflection of the electron beam the corner points |04 and |05 are coupled respectively by condensers |06 and |01 to the output terminals of a source |08 of high frequency deecting voltage. As in the previous CII instance this source is capable of supplying to these two corner points a push-pull saw-tooth voltage of considerable magnitude which is bal-. anced relative to ground( Likewise the corner points |09 and III areV coupled respectively by condensers ||2 and I I3 to a source ||4v of low frequency deecting Vvoltage which also is a balanced push-pull saw-tooth Voltage.

In addition, the corner points |04 and |05 are coupled respectively through isolating resistors ||5 and IIS and further through respective potentiometers I|'| and ||8 to a source of unidirectional voltage which is represented in the drawing as a battery ||0. The potentiometers I|`| and ||8 are arranged for simultaneous adjustment by means of a single control knob |2I. The corner points |00 and I similarly are coupled respectively through isolating resistors |22 and |23 and respective potentiometers |24 and |25 to the battery ||9. The potentiometers |24 and |25 also are arranged for simultaneous adjustment by a knob |26.

The network 93 is so constructed that the proper voltage distribution is effected to the various tube electrodes dependent upon their angular re-v lationship relative to an axis of symmetry of the electrodes. This is accomplished by selecting the proper impedance values for the resistors comprising each of the network branches. The impedance values of these resistors are so propor-y In this particular form of the network all resistors such as 98 and |0| which connect to corner points of the network are of equal values. In general, let w3 represent the impedance value of such resistors. The resistors such as 09 connected at the centers of each of the branches also are equal to one another in impedance which may be represented by wa In order to develop the desired voltages for impression upon the tub e electrodes, the ratio w4/w3 must be equal to \/2. The actual values of` these network resistors will depend upon the total impedance which is desired for the network.

The operation of the apparatus illustrated in Fig. 3 is substantially the same as that previously described in connection with Fig. 2. The high frequency deecting voltage derived from the source |08 is effective to produce a component of the eld within the tube whereby the electron beam is defiected over a target electrode at a relatively rapid rate in a horizontal direction, for example. The low frequency deflecting voltage derived from the source IIA is effective to produce a component of the field within the tube whereby the electron beam is deflected vertically relative to a target electrode at a relatively slow rate. The unidirectional voltages derived from the battery IIS are impressed upon the network 93 by the two pairs of potentometers ||`|-||8 and |24--|25'. A relatively constant component of the eld within the tube is produced by such means to suitably orient the electron beam .with respect to the target electrode. Adjustment of the beam orientation is accomplished horizontally by manipulation of the knob |2| and vertically by the knob |26.

Referring now to Fig. 4, there is shown another embodiment of the invention for use with a tube |31, also having eight elongated electrodes |28 uniformly spaced in `a circle aroundgthez-interior periphery of the tube envelope. In'this case, however,two pairs of opposite electrodes are located so that they lie respectively on the vertical and horizontal axes of the tube. The deflection of `the electron beam is to be eiectedgrelative to these axes.`

The tube electrodes are coupled to avoltage distributing network |23 by means, of which suitable :fvoltagesy are impressed upon theelectrodes to produceithe field necessary to effect the desired control of the electron beam.. As 'in;all forms of. the r invention, the network consists'fof. a balanced bridge arrangement of a plurality of impedance devices. The #connections-fof these impedance devices and` the respective values thereof is such that the networkhas a mirror electrical, symmetry about four4 axes eachvlocated ateangles of 45 degrees relativeto oneanotller.` The network |29 consists of four exterior branches I3I, |32, |33, and |34 connected Yineseries to form` a closed loop having two pairs of cornerfpoints |--.|36.fand |31`-|38.` The networkralso .includes four interior branches |39',` I 4 I, |42 anc`|.if|43:` The interior branches are connected finpairs^in series `between respective 'pairsoffcorner points: Foriexample, the intei-iorbranches |3$IandA |42 are connectedin series between thecorner points |35 and |36. Similarly, the interior Vbranches |4| `and |43 are connected in 4series between-'the corner points; Eiland-138.` The'mid-pointsof each of the two series connections of the-interior branchesl are 'connected together and,'as described. in.y connection with Fig. 2, preferably maybe grounded.

The sourcesfof. thevoltages which. it is` desired to distribute to the tube electrodes `bymeansztot the network 2B.' are illustrated in this-Iigure diagrammatically. A source |442of avoltagew1V iscoupled to the corner points |35'-.|36.f Another` source of a voltage V2 is similarlycoupled'to: the corner points |31"-|38. Itwillb'e lunderstoodthat the voltage sources I44-I/451may -Aiurnish either the deilecting.` vol-tages or the *center-ingrA voltages,.or both.

In this form of the invention; the :network |29 has two resistors in each of theexteriorand interior branches thereof;` For example, the exterior branch 31| consists of the series connection; of two resistors |46 and |41.' Atypical 'interior branch of the network such as the branch *|33 consists or the series connection 4of two resistors |48 fand |49. Selected intermediate tappointsV on `the network branches are connected respec tively to the various tube electrodes as indicated` by the Roman numerals. For example, the/tap.` or junction point |5|`between theresistors- |46r and`|41-oi the exterior network Vbranch |3|fisconnected to the tube electrode I,

The impedance values of the network components are selected todistributetheyoltages-A properly to the tube electrodes. Infeach of the exterior branches of the network the two resistors such as |46 and ,|41 ofthe branch. I3! are of the same impedance. As in previous cases, the total impedance of each of theexterior branches may be representedby ws. Also, the total impedance oi each ofthe interior branches such as theA branch |39 maybe represented by we. In this form of the invention, as in that disclosedA in Fig. 2, the relationship between resend-.ws is arbitrary. The two resistors comprising each: of theinterior branches such 4as the` resistors .|48 `and |49 of the branch |36` `are related'to one anotherY in impedance `in such, a mannerthat the value of,l`

' tion points of; the interior branches.

T4" theresistorz|48 andall others like itzinfthe other interior branches is substantially equal to 0.29320@ and the value of the resistor |49 and all Yothers like it in thezother interior branches is substantialy equal to 0.7071126.

The operation of the form of the invention illustrated 4in Fig. 4-is similar to that previously described in .connection with other forms of the invention and consequently need not rbe described in any further detail.

Referring nowto Fig. 5, there is shown a network capable of effecting the desired voltage distribution. to sixteen eld producingelectrodes o1k a cathode, ray tube. The electrodes (not shown) are uniformlyspaced in a circle around the linteriorperiphery ofthe tube envelope and arearranged as in Figs. 2 and 4, so that two pairs-,offopposite electrodes lie on tworcoordi.- nate axes of. the tube.

Forsuch atube there is. provided a `voltage distributing network; |52.Y It has. a form similartcathat yof all other. networks embodying :the inventionY and. consists of a balanced bridge arrangement of a plurality of impedance devices sofconnected; as to produceanetwork having a.

mirror electrical symmetry about four axes .located at angles of 45 degrees relative to oneV anotherri. In-.this case the network comprises four,;exterior-branches |53, |54, and |55 connected togetherin` series so as to. form aV closed loopzchavingf two pairs of-corner points |51|58 .and |5'-|6|.. Each of the exterior branches, such as the branch |53, consists of a series-connection of two resistors' |62 and |63.` The-:network also includes four interior branches |64;V |65,f|66 and: |61, each of which ismade up ofthe series connection of three resistors. The branch-|64,for example, includes resistors |68, |69 and |1|.' The interior branches |64 and |66 are connected together in series between the cornerepoints |51|58. The interior branches and |61 are connected in series between the corner: points` I 59|6|'. In thisY form ofthe invention'thefnetwork also includes four auxiliary branches |12, |13,A |14 and |15. The auxiliary branches-rare connected `in series to form a closedsloop` much in the same manner as the exterior branches are connected;V Each of the 1 auxiliary branches. consists of theseries connectionfof three resistors. The auxiliary branch |12,: foi-example, comprisesresistors |16, |11, |18. The `terminals of each of the auxiliary branches :are connected to intermediate junc- For 4example,` theterminal of the auxiliary branch |12 extending` from the resistor |16 is connected to the junction point between the interior branch resistorsv |69` and |1|. Corresponding terminals of allother :auxiliary `exterior branches are similarly'connected to the interior branches.

Afsource: |15 Cof 'a voltage Vl is coupled to the corner points itl-25S. Also, a source |8| of a Voltage V2 is connected to the corner points wil-|65. The network |52 is designed itc furnish `field producing voltages to sixteen electrodes of `a tube wherein the electrodes VIII and XIV lie on the vertical axis and kthe electrodes IV and XII lie on the horizontal axis. All of the tube electrodes are connected to selected intermediate or tap points on the network as indicatedby the Roman numerals.

The impedancerelationship `between .the various components of theinetworkarechosen.,.to

impress voltages upon the respective tube electrodes whereby to produce the desired i'leld for controlling the electron beam. The resistors employed in each of the exterior branches all are of equal impedance values. For example, in the exterior branch |53, the total impedance thereof may be represented by wu. In this case the values of each of the resistors such as 162 and H53 will be represented as 0.51m. The total impedance of each of the auxiliary branches such as |12 may be represented as wa. The resistors I and llt and all others like them in the other auxiliary branches are equal to 0.2931118. The value of the resistor Hl and all others like it of the other auxiliary branches is equal to 0.414108. The combined impedance of the resistors l68 and inof VVthe interior branch ili and all others like them of the other interior branches may be represented as ws. The impedance of the resistor 168 and all others like it is substantially equal to 0.765109. The impedance of theresistor IH and all others like it of the other interior branches is substantially equal to 0.08l'7w1wa/w7-l-wa. The relationship between the impedance values wv, vwas and wg are arbitrary and may be chosen to produce a network having any desired eective impedance.

The operation of the form of the invention illustrated in Fig. is substantially the same as the operation of all other forms of the invention and, therefore, will not be described.

The general character of the impedance networks in accordance with the present invention may be determined from a consideration of the typical examples which have been disclosed herein by way of illustration. As previously stated, the invention is not limited to any particular specific form of network so long as it is of such a character to satisfy certain underlying essentials. One of these essential requirements of a network within the scope of the invention is that it be a balanced bridge arrangement of a plurality of impedance devices. The character of the impedance devices is immaterial so long as, in a given network, they are all of the same kind. The arrangement of the impedance devices must be such that the network is provided with a plurality of pairs of conjugate corner points; one pair for each of the voltages which it is desired to distribute. The character of these voltages is immaterial to the successful practicing of the invention. They may be unidirectional voltages having xed or variable magnitudes. Also, they may be voltages of a periodic character such as an alternating Voltage which is cyclically variable as a function of time. Another requirement of a network falling within the scope of the invention is that it have a mirror electrical symmetry about all of a plurality of equiangular axes, as for example, four axes located at angles of 45 degrees relative to one another.

Such a network may be used to distribute voltages to a plurality of electrodes uniformly spaced around a circle, as illustrated herein. It does not matter whether pairs of opposite electrodes lie on axes of symmetry of the electrodes or whether these axes are located at an equal distance between adjacent electrodes. In either case the impedance devices of the network may be suitably proportioned to impress upon the electrodes respective voltages which are proportional to the angular relationships of the electrodes with respect to an axis of symmetry thereof.

It should be obvious from the foregoing description that practically any even number of voltages may be distributed to a plurality of electrodes by means of a network embodying the present invention. Also, it is considered to be apparent that, while for illustrative purposes a television tube operating according to the conventional rectilinear scanning pattern has been described, a net- Work of the character disclosed also is susceptible of use with other cathode ray tubes which may be operated according to substantially any other desired scanning pattern.

While there has been described what, at present, is considered the preferred embodiment of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the invention, and 'it is aimed, therefore, inthe appended claims to cover all such changes and modiiications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A system for controlling the direction of an electron beam comprising, 4k electrodes uniformly spaced in a circle around the path of said beam k being equal to any whole number, a voltage distributing network consisting of a balanced bridge arrangement of a plurality of branches having impedance, said branches being connected so as to give said network a mirror electrical symmetry about four axes located at angles of 45 degrees relative to one another, said network having two pairs of corner points, two sources of voltages VI and V2 connected to the respective pairs of network corner points, 4k tap points provided on said network branches, said tap points being connected respectively to said electrodes, and the impedances of said network branches being so proportioned to impress upon any given one of said electrodes located at an angle A rela tive to an axis of symmetry of said electrodes, a voltage proportional to V1 sin A-l-V2 cos A.

2. A system for deflecting an electron beam comprising, 47s elongated electrodes uniformly spaced in a circle around the path of said beam, Ic being equal to any whole number, a deecting voltage distributing network consisting of a balanced bridge arrangement of a plurality of impedance devices, said impedance devices being connected so as to give said network a mirror electrical symmetry about each of four axes located at angles of 45 degrees relative to one another, said network having two pairs of corner points, two sources of deiiecting voltages VI and V2 connected to the respective pairs of network corner points, 4k tap points provided in said network between certain ones of saidimpedance devices, said tap points being connected respectively to said electrodes, and the impedance devices of said network being so proportioned to impress upon any given one of said electrodes located at an angle A relative to an axis of symmetry of said electrodes, a voltage proportional to V1 sin A+V2 cos A.

3. A system for deilecting an electron beam comprising, a plurality of elongated electrodes located in spaced positions around the path of said beam, a deilecting voltage distributing net work consisting of a balanced bridge arrangement of a plurality of exterior branches connected together to form a closed loop and a plurality of interior branches connected between respective pairs of conjugate points of Said exterior branches, a source of high frequency deflecting :uvoltagefcoupled:toitone pair offsaidvconjugate networkV points, apsourceaofflow frequency `id'eecting .voltage coupledto the'fother painofsaidfconjugate network points,:andscuuplingssbetween peints on 4saidnetwork branchesand respective ones of said electrodespwhereby,toadeiectsaid :bearn'by all of said electrodes'in one: direction in response to said high frequency deilectinggvoltage and to'deflect said bearn'by` allof said' electrodes in another di rection in responseftofsaid lowfrequency deflect- Ving voltage.

LA systemrfor deiiecting an electron'beam -Acomprising,. a plurality-:of elongated electrodes located in spacedpositiens around the path of Said beam a deecting-:voltage distributing net- Work 'consisting of abalanced` bridge arrangement of a plurality of exterior branches connected together to form a closed 'loop' and an .equal number of interior branches-vcormected` in. pairs between respective pairs of conjugatepoints of said exterior branches, afsourceof high frequency deecting voltage coupledto one pair of said conjugate network:points, asource of low frequency deflecting voltage coupled to another pair of said 3 vconjugate network; points, and-couplings-between selected points `on said network branches and respective ones of saidelectrodes,` whereby to deilect said beam by all ofsaidfelectrodes in one direction in response to said high frequencyxdeflecting volt- -=age andto defiectsaid--beam by all of said electrodes inanother direction in'response to said low q frequency 'deflecting voltage.

5. A' systemfor deflecting an electron beam ,l comprising, a, plurality of elongated electrodes fi located in uniformly spacedv positions around the path of said beam, adeecting voltage distribut- ,l `ing network consisting of a balanced bridge arrangement of an even number of substantially s equal impedance exterior branches connected in x series to form a closedloop and an even number of substantially equal `impedance interior branches connected in pairs in series between respective pairs of `conjugatepoints of said exterior branches, a source of high frequency defleeting voltage'coupled to Vone pair of said conjugate network points, a source of low frequency deiiecting voltage coupled to another pair of said conjugate network points,v and couplings ber tween selected points'on saidnetwork branches and respective ones of said electrodes,` whereby ,v

to deflect said beam, by all of said electrodes in -one directionin response tosaid high frequency delecting'voltage and to deect said beamby all 1, ofssaid electrodes in another direction in response .to said low frequency deflecting voltage.

1 6; A system forfdeflecting an electron Vbeam comprising, a plurality of elongated electrodes located in uniformly spaced positions around the path of said beam, a delecting voltage distributing. network consistingof a balanced bridge arrangement of :four substantially equal impedance exterior branches connected in series to form a closed loop and four substantially equal impede; ance v interior `branches connected in-xpairs in se- 'tries between-respective pairs `of conjugate points vof said exterior branches; said'.interioi-branches being connectedtogether at' their midpoints, a

'rxsource Aof Ahigh frequency; Ydeflecting `voltage coupled to one pair of said'conjugate network spoints; a source offlowfrequency deiiecting voltage coupled to the other `pair; of said conjugate :zunetwork points, andl couplings betweenv selected J Apoints on said networkvbranches and respective '-:ones of said electrodes, whereby to deflect said 'znbeam by 'allof saidY electrodes-'in one directionv in Cil fil-8 response to Ysaidfhighfrequency-1deflecting voltage and to deflect said beam by all of said electrodes in another direction in response to said low frequency-deecting voltage.

7. A system forzdeecting an electron beam comprising, afplurality ofelongated electrodes located in uniformly spaced positions around the path of said beam, a deflecting voltage distributing network'consisting of a balanced bridge arrangement of four substantially equal impedance exterior branchesfconnected in series to form a closed loop and-four substantially equal impedance interior branches connected in pairs in series between respective pairs of conjugate points of said exterior branches, said interior branches being grounded-ati` their mid points for alternating voltages; ai'sourceof high frequency deecting voltage coupled to one pair of said conjugate network points, a source of low frequency deflecting voltagezicoupled vto the other pair of said conjugate-network points, and couplings between selected-fintermediate points on said network branches and-:respective ones of saidelectrodes, whereby 'todeilect said-beam by all of said electrodes in one direction in response to said high frequencyzdeflecting voltage and to deflect said beam byfallrpf ,said electrodes in another direction in response `=to `said low frequency deflecting voltage.

8. A systemzforfcontrolling` an electron beam relative to a targetelectrode comprising, a plurality of electrodes"-located`l around the path of said beam, a distributing network for beam-defleeting voltages; a1 distributingfnetwork for voltages by whichtotorient-saidbeam relative to said target electrode',"eachi of 'said networks -consisting of a balanced'bridgearrangement of a plurality of exteriorrbranches connected to form a closed loop and a plurality of interior branches connected betweenrespective 'pairs of conjugate points of said exterior'branches, a source of high frequency deectingfvoltage coupled to one pair of conjugate Apoints of t saidw deilecting voltagedistributing network; asource` of low' frequency deecting Voltagesconnectedto theother pair of conjugate pointspfzsaid deecting voltage-distributing network, couplings between points on said deecting voltage-distributing network branches and respective' ones of said electrodes, whereby to deflect 4said beam by all of said electrodes in one direction in response to said high frequency deecting l:voltage vandto deflect said beam by all of said electrodes in another direction in response to said low frequency deecting voltage, a source of unidirectional voltage coupled to each pair of conjugate points of said orienting voltage-distributing network, couplings between points on said orienting voltage-distributing network branches and-respectiveones of said electrodes, and meanszforvarying atleast one of the unidirectional voltages irnpressedupon the respective pairs of conjugate points of said orienting voltage-distributing network, whereby to control the orientationl of -said beam relative to said target electrode.

9. A system'forcontrollingan' electron beam relative to a target electrode comprising, a plurality of electrodes located around the path of said beam, a distributing network for beamdeecting voltages, a distributing network for voltages by which to orient said beam relative to said target electrode, each 'of said networks consisting of a balanced bridge arrangement of a pluralityT of exterior'branches connected together to forni a closedL loop-and an equal number of iterior branches connected in pairs between reoective pairs of conjugate points of said exerior branches, a source of high frequency deecting voltage coupled to one pair of conjugate oints of said deflecting voltage-distributing netrork, a source of low frequency deecting voltage onnected to the other pair of conjugate points i said delecting voltage-distributing network, ouplings between suitable points on said delecting voltage-distributing network branches ,nd respective ones of said electrodes, whereby to leilect said beam by all of said electrodes in one lirection in response to said high frequency delecting voltage and to deflect said beam by all f said electrodes in another direction in response o said low frequency deflecting voltage, a source lf unidirectional voltage coupled to each pair if conjugate points of said orienting voltagelistributing network, couplings between points )n said orienting voltage-distributing network )ranches and respective ones of said electrodes, rnd means for varying the unidirectional voltges impressed upon the respective pairs of conlugate points of said orienting voltage-distributng network, whereby to control the orientation )f said beam relative to said target electrode.

1G. A system `for controlling an electron beam relative to a target electrode comprising, a plu-4 rality of electrodes located in spaced positions around the path of said beam, a distributing network for beam-deecting voltages, a distributing network for voltages by which to orient said beam relative to said target electrode, each of said networks consisting of a balanced bridge arrangement of an even number of substantially equal impedance exterior branches connected in series to form a closed loop and an even number of substantially equal impedance interior branches connected in pairs in series between respective pairs of conjugate points of said exterior branches, a source of high frequency delecting voltage coupled to one pair of conjugate points of said deecting voltage-distributing network. a source of low frequencv deflecting voltage connected to the other pair of conjugate points oi said delecting voltage-distributing network. couplings between selected points on said deflecting voltage-distributing network branches and respective ones of said electrodes. whereby to deflect said beam by all of said electrodes in one direction in response to said high frequency defleeting voltage and to deflect said beam by all of said electrodes in another direction in response to said low frequency deflecting voltage, a source of unidirectional voltage coupled to each pair of coniugate points of said orienting voltagedistributing network, couplings between selected points on said orienting voltage-distributing network branches and respective ones of said electrodes, and means for varying the unidirectional voltages impressed upon the respective pairs of conjugate points of said orienting voltagedistributing network, whereby to selectively control the orientation of said beam in two coordinate directions relative to said target electrode.

1l. A system for controlling an electron beam relative to a target electrode comprising, a plurality of elongated electrodes located in spaced positions around the path of said beam, a distributing network for beam-deflecting voltages, a distributing network for voltages by which to orient said beam relative to said target electrode, each of said networks consisting of a balanced bridge arrangement of four substantially equal impedance exterior branches connected in series to form a closed loop and four substantially equal impedance interior branches connected in pairs in series between respective pairs of conjugate points of said exterior branches, a source of high frequency deiiecting voltage coupled to one pair of conjugate points of said deflecting voltagedistributing network, a source of low frequency deflecting voltage connected to the other pair of conjugate points of said deflecting voltagedistributing network, couplings between selected points on said deflectlng voltage-distributing network branches and respective ones of said electrodes, whereby to deect said beam by all of said electrodes in one direction in response to said high frequency deilecting voltage and to deiect said beam by all of said electrodes in another direction in response to said low frequency deflecting voltage, a source of unidirectional voltage coupled to each pair of conjugate points of said orienting voltage-distributing network, couplings between selected points on said orienting voltagendistributing network branches and respective ones of said electrodes, and means for varying the unidirectional voltages impressed upon the respective pairs of conjugate points of said orienting voltage-distributing network, whereby to selectively control the orientation of said beam in two coordinate directions relative to said target electrode.

12. A system for controlling an electron beam relative to a target electrode comprising, a plurality of elongated electrodes located in uniformly spaced positions around the path of said beam, a distributing network for beam-deecting voltages, a distributing network for voltages by which to orient said beam relative to said target electrode, each of said networks consisting of a balanced bridge arrangement of four substantially equal impedance exterior branches connected in series to form a closed loop and four substantially equal impedance interior branches connected in pairs in series between respective pairs of conjugate points of said exterior branches, a source of high frequency deflecting voltage coupled to one pair of conjugate points of said deflecting voltagedistributing network, a source of low frequency deflecting voltage connected to the other pair of conjugate points of said deectng voltage-distributing network, reactive couplings between selected intermediate points on said deecting voltage-distributing network branches and respective ones of said electrodes, whereby to deiiect said beam by all of said electrodes in one direction in response to said high frequency deflecting voltage and to deflect said beam by all of said electrodes in another direction in response to said low frequency deflecting voltage, a source of unidirectional voltage coupled to each pair of conjugate points of said orienting voltagedistributing network, conductive couplings between selected intermediate points on said orienting voltage-distributing network branches and respective ones of said electrodes, and means for individually varying the unidirectional voltages impressed upon the respective pairs of conjugate points of said orienting voltage-distributing network, whereby to selectively control the orientation of said beam in two coordinate directions relative to said target electrode.

13. A system for controlling the movement of an electron beam comprising, a plurality of electrodes uniformly spaced around the path of said beam, a voltage-distributing'network comprising a plurality of impedance devices connected to provide a balanced bridge, said network having anser-82a 21 twoipalrsof conjugate corner points' and a-plurality of tap pointsat selected intermediatepositionsv onsaid` impedance devices, a sourceof high frequency Idefiecti-ng =voltage-coupled to a first pair of lsaid corner points, a-sourceof low-frequency`v delecting voltage connected to asecond pairof -said corner points, a source of lunidirectional '--horizontallcentering voltage coupledto said rst pair of corner points, a source of unidirectional verticalcen-tering voltage coupled tosaidl second pairof corner points, andscouplings between said networkv tap points and respective ones of said electrodes, said network tap points bei-ng selected i soas to impress the beam-controlling voltages Aupon said'respective` electrodes in'suitable Vproportions to effect the production by all of said i electrodes of a-homogeneousleld'in the path of said beam.

14.V A systemI for controlling themovement-'of A an electron beam comprising, a plurality of electrodes uniformly spaced around theipath of'said l beam, a voltage distributing network comprising a plurality of impedance devices connected to provide a balanced bridge, said network having :utwo pairs of conjugate corner points and a plurality of tap points at selected intermediate positions on said impedance devices, a first source of each of two independent voltages coupled to a first pair of said -corner points, a second source of each of two independent voltages connected to a second pair of said corner points, and couplings between said network tap points and respective ones of said electrodes, said network tap points being selected so as Yto impress the beamcontrolling voltages Vjupon vsaid respective electrodes in suitable proportions to effect the production by all of said electrodes of a homogeneous iield in the path of said beam.

15. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, a plurality of electrodes uniformly spaced around the path of said beam, said electrodes being located relative to said coordinate axes so that the axes pass mid-way between predetermined adjacent electrodes, a voltage distributing network comprising a plurality of impedance devices connected to provide a balanced bridge, said impedance devices being connected in series to form a closed loop having two pairs of conjugate corner points and a plurality of intermediate tap points, means for impressing a irst voltage upon one pair of said conjugate corner points, means for impressing a second voltage upon the other pair of said conjugate corner points, and couplings between said network tap points and respective ones of said electrodes, whereby to control the movement of said beam by all of said electrodes in one direction relative to said coordinate axes in response to said first voltage and to control the movement of said beam by all of said electrodes in another direction relative to said axes in response to said second voltage, said network tap points being selected so as to impress the beam-controlling voltages upon said respective electrodes in suitable proportions to effect the production by all of said electrodes of a homogeneous eld in the path of said beam.

16. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, eight elongated electrodes uniformly spaced around the path of said beam, said electrodes being located relative to said coordinate axes so that the axes pass mid-way between predetermined adjacent electrodes, a voltage dis- 75 frtributi-ng netwerkecomprising a. balanced-bridge arrangement of four-substantially equal imped- -ance branches connected in series to forma closed loop having two pairs of conjugate corner points,` each-ofsaid branches being, provided with two intermediate tap points, means for impressing a .first voltage upon one pair of said conjugate corner points, means for impressing a second voltage upon the other pair of said conju- `vgate corner points and couplings between saidnetwork tap points and respective ones of said electrodes, whereby to control the movement of said `beam by all of saidelectrodes in one direction relative tosaid coordinate axes in response'to said rstV voltage-and to VcontrolV the movementV of said beam by all of said electrodes in another direction relative -to said axes in response to 1f said second voltage.

l?. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, a plurality of electrodes uniformly l spaced around the path of said beam, two pairs of opposite electrodes lying respectively on said '.two axes, a voltagedistributing network comprising a balanced bridge arrangement ofA a plurality of 'substantially equal impedance TeX- teriorl branches connected in series to form a closed loop and a plurality of substantially equal impedance interiorbranches connected in pairs in series between respective pairs of conjugate points of said exteriorbranches, each of said i network branches being provided with at least :one intermediate tap point, means for impressing a lirst voltage upon one pair of said conjugate network points, means for impressing a second voltage upon the other pair of said conjugate network points, and couplings between said network tap points and respective ones of said electrodes, whereby to control the movement of said beam by all of said electrodes in one direction relative to said coordinate axes in response to said i'lrst voltage and to control the movement of said beam by all of said electrodes in another direction relative to said coordinate axes in response to said second voltage.

18. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, twelve elongated electrodes uniformly spaced around the path of said beam, two pairs of opposite electrodes lying respectively on said two axes, a voltage distributing network comprising a balanced bridge arrangement of four substantially equal impedance exterior branches connected in series to form a closed loop and four substantially equal impedance exterior branches connected in pairs in series between respective pairs on conjugate points of said exterior branches, each of said exterior branches being provided with two intermediate tap points and each of said interior branches being provided with one intermediate tap point, a source of a rst voltage coupled to one pair of said conjugate network points, a source of a second voltage coupled to the other pair of said conjugate network points, and couplings between said network tap points and respective ones of said electrodes, whereby to control the movement of said beam by all of said electrodes in one direction relative to said coordinate axes in response to said rst voltage and to control the movement of said beam by all of said electrodes in another direction relative to said axes in response to said second voltage.

19. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, a plurality of electrodes uniformly spaced around the path of said beam, a Voltage distributing network comprising a balanced bridge arrangement of a plurality of substantially equal impedance exterior branches having intermediate tap points and connected in series to form a closed loop having two pairs of corner points, a plurality of substantially equal impedance interior branches having intermediate tap points and connected in pairs in series between respective pairs of corner points of said exterior branches and a plurality of substantially equal impedance auxiliary branches having intermediate tap points `and connected in series to form a closed loop having two pairs of conjugate points connected respectively to corresponding tap points on said interior branches, means for impressing a rst voltage upon one pair of said corner network points, means for impressing a second voltage upon the other pair of said corner network points, and couplings between said network tap points and respective ones of said electrodes, whereby to control the movement of said beam by all of said electrodes in one direction relative to said coordinate axes in response to said first Voltage and to control the movement of said beam by all of said electrodes in another direction relative to said coordinate axes in response to said second voltage.

20. A system for controlling the movement of an electron beam relative to two coordinate axes comprising, sixteen elongated electrodes uniformly spaced around the path of said beam, two pairs of opposite electrodes lying respectively on said two axes, a voltage distributing network comprising a balanced bridge arrangement of Cil four substantially equal impedance exterior branches h-aving intermediate tap points and connected in series to form a closed loop having two pairs of corner points, four substantially equal impedance interior branches having intermediate tap points and connected in pairs in series between respective pairs of corner points of said exterior branches and four substantially equal impedance auxiliary branches having intermediate tap points and connected in series to form a closed loop having two pairs of conjugate points connected respectively to corresponding tap points on said interior branches, a source of a rst voltage coupled to one pair of said corner network points, a source of a second voltage coupled to the other pair of said corner network points, and couplings between said network tap points and respective ones of said electrodes, whereby to control the movement of said beam by all of said electrodes in one direction relative to said coordinate axes in response tosaid first voltage and to control the movement of said beam by all of said electrodes in another direction relative to said coordinate axes in response to said second voltage.

HANS W. G. SALINGER.

REFERENCES CITED UNITED STATES PATENTS Name Date Alexanderson et al. Jan. 21, 1947 Number 

